Automatic fire extinguishers generally are comprised of a container for fire extinguishing material (or "extinguishant") which may be mounted by means of a housing on a wall or other suitable place. The container is typically cylindrical in shape and tapers in at the top. There is a manifold at the top of the container into which an automatic actuator may be engaged. The extinguishant in the container is kept under pressure. Inert chemicals such as halon are typically used for the extinguishant.
The automatic actuator closes off the manifold of the fire extinguisher. The automatic actuator may be similar in design to an automatic sprinkler head for an automatic sprinkler system. The automatic actuator is usually comprised of a body which is exteriorly threaded for engagement with the manifold of the container. The body of the automatic actuator has a passageway for the extinguishant. The passageway is sealed off by a closure element, or plug. A frame with two arms extends outward from the body and joins opposite the passageway. A deflector plate is attached to the frame opposite the passageway. A trigger element, such as a thermally responsive glass bulb or heat fused solder element, holds the closure element closed. The trigger element is designed to break, or fracture, at a predetermined temperature. When the trigger element breaks, the closing force exerted on the closure element is removed, and the closure element is pushed away from the passageway by the force of the pressurized extinguishant in the container.
In addition to automatic actuation, it is useful for an automatic fire extinguisher to be capable of manual actuation because there may be circumstances in which the need for the fire extinguisher arises before the heat-sensitive automatic actuator has triggered. Such circumstances may be caused, for example, if the fire extinguisher is for some reason shielded from the fire, or if it is too far from the fire to be automatically actuated. Hence, automatic fire extinguishers are sometimes equipped with manual actuators, in addition to automatic actuators.
Manual actuators which may be factory-installed on automatic fire extinguishers are known in the art. For example, lever arm and hoop arrangements, lever pull-arms and other types of cable and/or lever arrangements have been used for manual actuation systems. At least some of these designs, however, have used a part which wraps around the trigger element of the automatic actuator, which may shield the trigger element from its surroundings and thereby result in decreased responsiveness of the automatic actuator. Moreover, there is a need for manual actuators which may be readily field-installed by an owner or user of an automatic fire extinguisher, since many automatic fire extinguishers are not equipped with manual actuators at the factory. An owner of an automatic fire extinguisher that is not equipped with a manual actuator may find it preferable and cheaper to simply add a manual actuator to his or her automatic fire extinguisher, rather than obtain a new fire extinguisher that comes from the factory so equipped.
While prior art manual actuators may theoretically be capable of field installation, such installation may be carried out only with difficulty and, in some instances, only by removing or redesigning parts of the automatic fire extinguisher. To be effective, however, field installation, or field mounting, should be able to be accomplished in a matter of minutes and without removing or redesigning parts of the automatic fire extinguisher. Otherwise, the owner or user of an automatic fire extinguisher may be deterred from installing a manual actuator because of the excessive complexity and time that may be required to mount or install a manual actuator on the fire extinguisher. Hence, the terms "field installation" or "field mounting", as used herein, refer to the ability to mount the manual actuator on the fire extinguisher in a matter of minutes, without removing or redesigning parts of the fire extinguisher.
In addition, manual actuators known in the art have not always been easily adaptable to the particular positioning needs of the place in which the fire extinguisher is to be used. For example, various manual actuators known in the art may be installed at the factory for actuation from the right hand side of the extinguisher, or, alternatively, may be installed for actuation from the left hand side of the extinguisher. However, if the extinguisher is to be placed in a narrow or otherwise tight space, it may be that the extinguisher can be manually actuated only from the side opposite that from which the extinguisher was designed to be manually actuated. While the cylinder of the fire extinguisher may be rotated to avert this problem, such rotation may result in the fire extinguisher being positioned in a direction which does not generate the optimum spray pattern. Hence, it is useful for a manual actuator to be capable of ready adaptation for actuation from either side of the automatic fire extinguisher, without having to change the direction in which the fire extinguisher is pointed.